Work machines can often include interchangeable hydraulically-driven implements. By altering the hydraulically-driven implement attached to the work machine, the function of the work machine can also be altered. For instance, various implements, including but not limited to, an auger, a bucket and a pickup broom, can be attached to a skid steer loader. When the auger is attached to the skid steer loader, the skid steer loader can be used for drilling holes; whereas, when the pickup broom is attached to the skid steer loader, the skid steer loader can be used for removing and dumping material. However, in order for the work machine to include interchangeable implements, there must be a method of disengaging the hydraulically-driven implement from the work machine.
Engineers have long known that opening a closed hydraulic system, such as a hydraulic system connecting the hydraulically-driven implement to the work machine body, can be difficult, and often undesirable, when high pressure is trapped within the system. Over the years, engineers have developed electrical and mechanical methods for overcoming these problems. For instance, there are apparatuses, such as that shown in U.S. Pat. No. 6,032,537, issued to McLaren, on Mar. 7, 2000, that detect high pressure within a hydraulic system and bleed the high pressure to a low pressure reservoir prior to opening the hydraulic system. Although these pressure relieving methods have found use in various situations, many of the methods have not been applied to aid in the disengaging of an interchangeable hydraulically-driven implement from a work machine, such as a skid steer loader.
The hydraulically-driven implement is generally attached to the body of a skid steer loader by two hydraulic lines connected to two attachment ports of the skid steer loader. Two valves included within the work machine control the flow of hydraulic fluid to and from the implement. In order to operate the implement in one direction, a first valve will be moved to a position that allows high pressure hydraulic fluid to flow through the first port and the connected hydraulic line. A second valve will connect the second hydraulic line to the low pressure reservoir. Thus, high pressure fluid will flow through the first hydraulic line, do work within the implement, and flow out the second hydraulic line to the low pressure reservoir. In order to move the hydraulically-driven implement in a second direction, the second valve will connect the second hydraulic line to the source of high pressure fluid, while the first valve will connect the first hydraulic line to the low pressure reservoir. Thus, the implement will move in a second direction.
When the engine of the skid steer loader is de-activated, high pressure fluid flowing through the implement may remain within one or both of the hydraulic lines. Thus, when the operator attempts to detach the implement from the skid steer loader, the trapped high pressure fluid can make it difficult to disconnect the hydraulic lines from the attachment ports via quick disconnectors. Sometimes, operators may resort to unsafe and/or destructive techniques to disconnect the hydraulic lines, such as prying apart the disconnectors with work tools. The difficulty in disconnecting the implement may become burdensome on the operator when changing implements. Moreover, if the operator de-activates the implement when it is in a position which requires pressurized fluid to remain, the implement may react to the release of pressure by unexpectedly moving. Thus, if the operator is disonnecting the hydraulic lines from the attachment ports when the pressure is released, the operator may be at risk for injury.
The present invention is directed to overcoming one or more of the problems set forth above.